Backlit labels are often used on electronics products to make users aware of information such as the manufacturer, model number, system status, or function of a button. As the name implies, backlit labels are lit from behind, typically from within the electronics housing using a light source such as a light emitting diode (LED). Functional concerns of the electronics product usually dictate the configuration of the housing, leading to various problems lighting backlit labels.
A common method for lighting backlit labels is to place one or more LEDs directly behind the label. This use of discrete LEDs often requires additional wiring to power the LED, which may complicate design and drive up assembly costs. Discrete LEDs may also have a drawback of unevenly lighting the label, creating hotspots of light close to each LED and dark unlit portions of the label between the LEDs and near the edges, which may make the backlit label difficult to read.
Variations of discrete LEDs include LEDs with wide-angle or diffused lenses to disperse the light before reaching the label. Another variation, an LED bar, attempts to provide uniform light with an array of LEDs. While these variations help somewhat with the problem of uneven lighting, they still require additional wiring to power the LEDs and do not always fit a given case design. Diffused lenses, for example, require the LED to be placed a significant distance from the label, where it may be difficult to provide power.
Another known method is to use one or more light pipes to guide light from LEDs placed on a printed circuit board to the label. Light pipes help reduce the cost of wiring and assembly because the LEDs are incorporated in the printed circuit board. Light pipes, however, may still suffer from the problem of uneven lighting. The emitting ends of the light pipes act similarly to discrete LEDs, creating hotspots and unlit portions.
In view of the foregoing, it would be desirable to provide a lighting device to evenly backlight labels. In particular, it would be desirable to provide a label backlighting device that reduces the appearance of hotspots and unlit portions in the label. Furthermore, it would be advantageous for design and cost if the lighting device does not require additional wiring to be placed near the label.